Bw. Soong et Rs. Liu, POSITRON-EMISSION-TOMOGRAPHY IN ASYMPTOMATIC GENE CARRIERS OF MACHADO-JOSEPH-DISEASE, Journal of Neurology, Neurosurgery and Psychiatry, 64(4), 1998, pp. 499-504
Objectives-The metabolic changes in the brain of symptomatic subjects
affected with Machado-Joseph disease have been previously documented u
sing PET with fluorine-18-fluorodeoxyglucase (FDG). The aim of this st
udy was to evaluate these changes in asymptomatic, Machado-Joseph dise
ase gene carriers. Methods-Seven asymptomatic Machado-Joseph disease g
ene carriers, identified using a molecular test, and 10 normal control
subjects were recruited for PET studies using FDG. Regional uptake ra
tios of FDG were calculated from the radioactivity of the cerebellar h
emispheres, brainstem, and the temporal, parietal and occipital cortic
es, divided by the activity in the thalamus. Results-In comparison wit
h data obtained from normal control subjects, there was significantly
decreased FDG utilisation in the cerebellar hemispheres, brainstem, an
d occipital cortex, and increased FDG metabolism in the parietal and t
emporal cortices of asymptomatic Machado-Joseph disease: gene carriers
, suggesting preclinical disease activity. Discriminant analysis of re
gional FDG uptake correctly classified genetic status (Machado-Joseph
disease: mutation carriers v mutation negative subjects) in 25 of 25 s
ubjects (100% sensitivity and 100% specificity), and clinical status (
asymptomatic mutation carriers v symptomatic patients) in 14 of 15 sub
jects (100% sensitivity and 85.7% specificity).Conclusion-Subclinical
changes of FDG consumption, as measured by noninvasive PET, can act as
an objective marker of preclinical disease activity in Machado-Joseph
disease.